An electrochemical sensor incorporating a signal enhancement for the determination of lead （II） ions （Pb2＋） was designed on the basis of the thrombin-binding aptamer （TBA） as a molecular recog- nition element a...An electrochemical sensor incorporating a signal enhancement for the determination of lead （II） ions （Pb2＋） was designed on the basis of the thrombin-binding aptamer （TBA） as a molecular recog- nition element and ionic liquid supported cerium oxide （CeO2） nanoparticles-carbon nanotubes compo- site modification. The composite comprises nanoparticles CeO2, multi-waU carbon nanotubes （MWNTs） and hydrophobic room temperature ionic liquid （RTIL） 1-ethyl-3-methylimidazolium tetrafluoroborate （EMIMBF4）. The electrochemical sensors were fabricated by immersing the CeOa-MWNTs-EMIMBF4 modified glassy carbon electrode （GCE） into the solution of TBA probe. In the presence of Pb2＋, the TBA probe could form stable G-quartet structure by the specific binding interactions between Pb2＋ and TBA. The TBA-bound Pb2＋ can be electrochemically reduced, which provides a readout signal for quantitative detection of Pb2＋. The reduction peak current is linearly related to the concentration of Pb2＋ from 1.0 ＊ 10-8 M to 1.0 ＊ 105 M with a detection limit of 5 ＊ 109 M. This work demonstrates that the CeOz-MWNTs-EMIMBF4 nanocomposite modified GCE provides a promising platform for immobi- lizing the TBA probe and enhancing the sensitivity of the DNA-based sensors.展开更多
Current machinery requires metallic materials to have better surface properties. Based on an orthogonal experimental design and analysis method, the CeO2-rein- forced nickel nano-composite coatings were prepared by di...Current machinery requires metallic materials to have better surface properties. Based on an orthogonal experimental design and analysis method, the CeO2-rein- forced nickel nano-composite coatings were prepared by direct current electrodeposition in a nickel sulfate bath containing CeO2 nanoparticles. Statistical results indicate that current density is the most significant variable in the electrodeposition processing, while temperature is the least important factor. The microstructure of Ni and Ni-CeO2 nano-composite coatings was characterized by scanning electron microscopy （SEM） equipped with energy-disper- sive spectroscopy （EDS）, and X-ray diffraction （XRD）. The microhardness of the Ni coating is enhanced by the incorporation of CeO2 nanoparticles. Potentiodynamic polarization and electrochemical impedance spectroscopy （EIS） were used to characterize the corrosion behavior of Ni and Ni-CeO2 coatings. These studies show that Ni- CeOz coating has better corrosion resistance compared to Ni coating.展开更多
基金supports from the National Science Foundations of China (Nos. 20875076 and 21005061)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20096101120011)+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China (No.2010JQ2013)the Education Department of Shaanxi Province,China (No. 09JK759)the NWU Graduate Innovation and Creativity Funds (No. 09YSY04)
文摘An electrochemical sensor incorporating a signal enhancement for the determination of lead （II） ions （Pb2＋） was designed on the basis of the thrombin-binding aptamer （TBA） as a molecular recog- nition element and ionic liquid supported cerium oxide （CeO2） nanoparticles-carbon nanotubes compo- site modification. The composite comprises nanoparticles CeO2, multi-waU carbon nanotubes （MWNTs） and hydrophobic room temperature ionic liquid （RTIL） 1-ethyl-3-methylimidazolium tetrafluoroborate （EMIMBF4）. The electrochemical sensors were fabricated by immersing the CeOa-MWNTs-EMIMBF4 modified glassy carbon electrode （GCE） into the solution of TBA probe. In the presence of Pb2＋, the TBA probe could form stable G-quartet structure by the specific binding interactions between Pb2＋ and TBA. The TBA-bound Pb2＋ can be electrochemically reduced, which provides a readout signal for quantitative detection of Pb2＋. The reduction peak current is linearly related to the concentration of Pb2＋ from 1.0 ＊ 10-8 M to 1.0 ＊ 105 M with a detection limit of 5 ＊ 109 M. This work demonstrates that the CeOz-MWNTs-EMIMBF4 nanocomposite modified GCE provides a promising platform for immobi- lizing the TBA probe and enhancing the sensitivity of the DNA-based sensors.
基金financially supported by the National Natural Science Foundation of China (No.61674141)the Natural Science Foundation of Liaoning Province Department of Science and Technology (No.201602401)+2 种基金the Natural Science Foundation of Liaoning Province Department of Education (No.L2015259)Anshan City Science and Technology Plan Project (No.20153413)the National Training Programs of Innovation and Entrepreneurship for Undergraduates (No.201610146027)
文摘Current machinery requires metallic materials to have better surface properties. Based on an orthogonal experimental design and analysis method, the CeO2-rein- forced nickel nano-composite coatings were prepared by direct current electrodeposition in a nickel sulfate bath containing CeO2 nanoparticles. Statistical results indicate that current density is the most significant variable in the electrodeposition processing, while temperature is the least important factor. The microstructure of Ni and Ni-CeO2 nano-composite coatings was characterized by scanning electron microscopy （SEM） equipped with energy-disper- sive spectroscopy （EDS）, and X-ray diffraction （XRD）. The microhardness of the Ni coating is enhanced by the incorporation of CeO2 nanoparticles. Potentiodynamic polarization and electrochemical impedance spectroscopy （EIS） were used to characterize the corrosion behavior of Ni and Ni-CeO2 coatings. These studies show that Ni- CeOz coating has better corrosion resistance compared to Ni coating.
